Stuck on Zendesk ticket ID mapping in Genesys Bot

Background

Migrating Zendesk ticket data to Genesys Cloud bots. Trying to pass the Zendesk ticket ID as a custom attribute.

Issue

The bot fails to recognize the attribute during the handoff to a human agent. Getting a 400 Bad Request on the /api/v2/interactions endpoint. The payload includes custom_attributes.zd_ticket_id but the agent console shows it as null.

Troubleshooting

Verified the attribute exists in Architect. Checked the webhook payload from Zendesk. It arrives correctly. The issue seems to be in the Genesys interaction creation step. Am I missing a mapping step in the bot flow?